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PortRAY User Guide & Manual Version 0.11 April 1994 Page :1 PortRAY Development Team reserves the right to change Any and all details within this manual or the accompanying software with no prior warning. Acknowledgments Darren Hewson - Early work on manual Paul Smith - RayTECH BBS, and for supplying the Private development area on RayTECH BBS. And MANY thanks to the following people for their suggestions and testing of early versions of PortRAY. Raymond Ore Martin Higgs Joe Miller And all the others that have taken the time to have a look at PortRAY and returned their comments and suggestions. Contents Page No 1 - Introduction 3 2 - Ray-Tracing 4 What is Ray-Tracing 4 3D Geometry 4 How does Ray-Tracing Work 5 Anti-Aliasing 5 Creating A Scene 5 3 - PortRAY 6 4 - Camera Files 5 - The Scene File 6 - Lights 7 - Primatives 8 - Materials 9 - Shaders 10 - Define Appendix A. Descriptions of example files Appendix B. Descriptions of errorlevel values Page: 2 1. Introduction PortRAY is a European ray tracer, that is 100% ANSI C Complaint, this means that it can be re-compiled and run on any platform that supports ANSI C, this also means that there is no way to view the output from PortRAY while it is being rendered, this is because of the diverse video and graphic standards that would have to be included, to support all known ANSI machines. I have not included viewing, because ALL platforms have an abundance of tools and utilities to view and manipulate graphic images so I did not feel that a renderer that could not view was too serious a hindrance. 2. Raytracing ------------- What is Ray-tracing ? Ray-tracing is a technique used to produce 'photo- realistic' images from your computer. It works by simulating rays of light (hence Ray-tracing) in a 3d model described by the user. As it uses simulation of light, real optical effects such as reflection, refraction and shadows can be recreated. You do not particularly need any programming or artistic skills to produce a Ray-traced image although an ability to think in 3 dimensions is invaluable. You wont believe the images you can create............. check out the example files. Skull.gif 3D Geometry At school everybody met Geometry, although this invariably would have been the 2D variety. If I can drag you back a few years you will remember that a point in 2D space can be described by two co-ordinates commonly referred to as x and y. 7 | Y 6 | .(7,6) 5 | 4 | 3 | 2 | 1 | ------------------- 1 2 3 4 5 6 7 8 9 X In the example above the point is described by the x,y co-ordinate (7,6), that is 7 units up and 6 across. Any two dimensional shape can be described using this system. To make the transition to 3D geometry all you need do is add the third dimension which is known as 'z'. You can imagine the z direction as coming straight out of the screen toward you ! Y | | | | |____________________ / X / / / Z / Any point in 3D space can described by it's co-ordinates x,y,z. In the above system the point at which the x,y,z axes cross is called the origin, at the origin x = y = z = 0. How does it Work ? The ray-tracer 'shoots' a ray of simulated light from the 'eye' through each pixel on the screen into your 3D world (these are referred to as eye rays), the colour of the pixel on the screen is determined by the colour and intensity of the light and the colour and physical properties of any objects that the ray meets. Rays can be reflected or refracted depending on the properties of objects in the scene, each time this happens the light will acquire a little of the colour of the surface it reflects from. Anti-Aliasing For each pixel in the screen a ray-tracer normally generates one eye ray (a ray of light entering the camera/eye), other rays are generated by reflection and refraction. However in certain circumstances this can lead to 'jagged' edges to the objects in your scene (especially at low resolutions). To overcome this a technique called anti-aliasing is used. This effectively shoots a number of rays at different parts of the pixel and averages the resulting colour to produce a smoother transition at the edge of objects. (see section 3.1 - Cameras for details of PortRAY implementation). How do I create a Scene ? The 3D world you describe is constructed out of 'primitives'. A primitive is an object such as a sphere that can be given a position size colour and texture in a scene. You create the scene by defining the necessary primitives in a text file which is then processed and rendered by PortRAY. 3. PortRAY Raytracer -------------------- There are three components required to generate a PortRAY raytrace, they are 1) CAMERA statement 2) IMAGE statement 3) scene statements (either object, define, light, material) These can be grouped into one or two files, the first in the CAMERA file, which can contain CAMERA, LIGHT and IMAGE statements, but NOT scene statements. And the second is the SCENE file, that can contain all three different sections. If you wish, you can define one file (the SCENE file) to contain all three sections, and so not need a seperate camera file. Both the scene and camera (if applicable) description files needed to produce a raytraced image from PortRAY should be in standard ASCII text. PortRAY has a scene description language that is described in later sections. However the general syntax used throughout scene and camera description files is :- <Keyword> [<Variable Name> <Value>] ; The <Variable Name> <Value> block is often repeated. Also <variable name> can be another keyword. Command blocks are terminated with a semi-colon. So, for instance, the command to create a spherical object is; Object Sphere Centre (x y z) Radius r ; ; This terminates the shape definition-^ This terminates the OBJECT definition--^ Keywords can be in any case, and need not be on the same line, so the following is exactly the same as the above Object Sphere Centre (x y z) radius r ; ; Note how in this example the ; terminators are lined up with the keyword they terminate and subsequent keywords are indented. Using this notation may help to keep your object files organised and avoid syntax errors. All objects in PortRAY have default values so that simple images can be rendered, using the above example Object Sphere ; ; will produce a white sphere at position 0 0 0 with radius 1 A file can be included in another by the use of the include statement. Include statements cannot appear inside other statements. The format is as follows: include filename.ext Comments are enclosed in tilde "~" Signs. E.G. ~This is a comment line and will be ignored by PortRAY ~ Anything on a line after the '//' pair, is also treated as a comment, 4 Camera Files -------------- The camera file tells the renderer where to place the camera, what screen resolution to use, and if needed what lights should be included for this particular camera. Camera Statement The camera section of the camera file details the geometry and capabilities of the camera to be used for the rendered output. The following is a fully specified camera file:- camera look-at (0.0 0.0 0.0) drop-line (0.0 -1.0 0.0) look-from ( 0.0 5.0 -25.0) depth 0.028 x-size 0.032 y-size 0.024 filter adaptive ; filter lens samples 10 focal-length 30.0 radius 0.1 ; filter super-sample x-samples 3 y-samples 3 ; filter disk samples 10 radius 0.707 ; ; look-from: Is the point at which the pinhole or lens of the camera is positioned (not to be confused with the scene origin). look-at: Is the point at which the camera is pointing. drop-line: This is used to form the x co-ordinate vector of the screen. In effect this allows you to alter the x,y,z directions of the co-ordinate system (as outlined in section 1). It is probably not a good idea to mess around with this unless you are experienced. depth: x-size: y-size: are the physical dimensions of the camera. Filters Filters define the properties of the camera lens (pinhole or lens) and the pixel sampling technique used (anti-aliasing - see section 2). Filters are cumulative, they can be layered on top of each other indefinitely (subject to RAM), if for instance you take the sample below filter standard filter lens samples 10 focal-length 30.0 radius 0.1 ; filter super-sample x-samples 3 y-samples 3 ; filter disk samples 10 radius 0.707 ; This will generate 900! eye rays for each pixel on screen 10x3x3x10, this is obviously too many, they are all included with all sub-functions simply as an example. Generally you would use 1 and in some very rare circumstances 2 anti-aliasing filters, the standard filter, and for final images where realism is important the lens filter if needed. Standard This, or the adaptive filter MUST always be present, it is the filter that turns camera and film geometry into instructions to shoot rays into the scene. It must always be the first filter mentioned in the camera section, any listed before this will be ignored. Adaptive This filter implements Adaptive anti-aliasing. This variety of anti-aliasing adjusts the number of samples it makes dynamically according to the parameters you provide it. If the variance (in colour )between the corners of a pixel/sub-pixel is greater than the defined limit then the pixel/sub-pixel will be split up and resampled Variables: Threshold <float> : This sets the limit at which further samples are to be taken. If the difference in colour between the pixel or sub-pixels in question is less than this then no further samples will be taken. Default : 0.2. Max-depth <int> : This defines the maximum numbe of levels the re-sampling will continue to. Default : 3. cache-size <int> : This is the size of cache to use to store previous trace results, this enables the system to cut out renders of a section that has already been traced NORMALLY this will not need to be changed. Default : 1000 Relax <float> : At each successive level, the THRESHOLD is multiplied by the RELAX figure, this forces early bottom-out at lower levels if the difference between corners is slightly larger, for instance at level 0, a small variance causes a section to be recursed, but at lower levels, the variance is not so important. Default : 1.2 SuperSample This is an Anti-Aliasing filter, it subdivides each pixel into a regular grid and shoots a ray through each cell in the grid. Variables X-Samples <int> : The number of samples to take in the x direction Default : 2 Y-Samples <int> : The number of samples to take in the y direction Default : 2 Disk This is an Anti-Aliasing filter, it generates random rays in a disk about the centre of the pixel and accumulates the results,weighted by distance from the centre (i.e. in centre = 1.0 at circumference of disk = 0.0) The more samples the better but above about 20 no difference is apparent. Variables Radius <float> : The radius of the circle within which samples are to be generated Default : 0.707 Samples <int> : Number of Samples to generate within the disk Default : 4 Lens This Filter simulates a perfect lens (NO chromatic abberation) and allows depth of field and blurred images, the higher the number of samples, the better quality of image, but about 20 no discernible difference is apparent (Apart from the RUN time!) Variables Radius <float> : The radius of the lens to simulate (Note NOT the radius of curvature, but the actual aperture radius) Default : 0.1 Focal-Length <float> : The Distance from the lens from which rays will focus clearly onto the film Default : 1000.0 Samples <int> : The number of samples to trace through the lens Default : 4 Image Statement The image statement sets up the image resolution and some aspects of image quality. image xsize 320 ysize 240 no-shadows no-reflections nonstop Intersect-Buffer 1000 ; The above image statement selects an output image resolution of 320x240 pixels and specifies no shadow and no reflection calculations, this can be used to check images prior to rendering at higher resolutions and more realistic rendering. The render cannot be interrupted with anything less than a ctrl-c. Also the number of entries in the cache used during adaptive anti-aliasing is specified in this example, but need not be. (The default value is 1000) 5 The Scene File ---------------- The scene file is where you describe the primatives that make up your scene. Different objects may be defined in different scene files and brought together by using the 'include' statement. See Example file : dice.sce Scene files can also include lights and declarations of materials. A good practice is to use 'sce' as the extension for your scene files. 6 Lights -------- What is a picture without light ? This is a critical aspect of most art, be it computer generated or hand drawn/painted. It is especially true of Ray-tracing, the whole appearance of an image can be altered by just tweaking the lights. In PortRAY lights can be defined with the camera or the scene. The light definition tells PortRAY what attributes each light has. For instance colour position and shape. Below is a typical light source definition. light colour (1.0 1.0 1.0) position (-10.0 20.0 -5.0) shape sphere centre (-10 20.0 -5.0) radius 2.6 ; samples 20 fall-off 1 no-shadows ; This defines a spherical light source with a centre at -10, 20, -5 and a radius of 2.6 and a colour of white, shadows from this light source will be sampled at 20 random positions on the surface of the sphere. The light intensity will fall off at a linear relation to the distance that the light travels, and no shadow intersection tests will be done against this light source. Values of fall off are 0 - No Fallof 1 - linear falloff 2 - squared falloff Note, these are only examples, the user is free to use any positive real value for falloff, so 1.2 or 3.5 are also valid falloff values. Shapes (primitives) supported for light sources are: Sphere - standard spherical light source Cylinder - flourescent strip lighting ? Box - Use your imagination 7 Primitives ------------ Primitives are the shapes that you use to define your scene. Each primitive has colour and/or surface texture (defined via 'material') associated with it, and can also be stretched or shrunk along all three axes. Scaling, rotation, translation. This is accomplished using the shrink/stretch commands as follows Look at shrink-x <float> : contracts the x-axis shrink-y <float> : contracts the y-axis shrink-z <float> : contracts the z-axis stretch-x <float> : expands the x-axis stretch-y <float> : expands the y-axis stretch-z <float> : expands the z-axis translate <vector> : Moves the object so that the <vector> defines the origin for the object definition x-rotate <float> : Rotates about the x axis in degrees y-rotate <float> : " " " " y " " " " z-rotate <float> : " " " " z " " " " The primitives currently available within PortRAY are as follows: Spheres Planes Cylinders Triangles Boxes Raw data files CSG (Constructive Solid Geometry, INTERSECT, UNION, SUBTRACT) Disks Polygons (Concave, convex, complex (multiple contours)) Sphere I think it's fairly obvious what this primitive does, so I'll skip the long description ! The variables used to decribe a sphere are listed below:- Required Variables: Centre <vec> : A point defining the centre of the sphere Radius <float> : The radius of the sphere Optional Variables: Pole <vec> : A vector describing the north pole of the sphere. IE a line running through the centre of the sphere. This variable is only required if you wish to map a 'material' on to the sphere. Equator <vec> : A vector that defines what position the longitudinal axis starts at. Examples: A simple sphere definition would be: object sphere centre (0.0 0.0 0.0) radius 4.0 ; ; This would define a sphere with radius 4.0 centred on the origin. Plane A plane primitive describes an infinite plane in 2 dimensions with no "thickness" in the third dimension. Required Variables Position: This variable simply tells PortRAY where the plane should be placed. Normal: A vector describing the normal of the plane, this determines the orientation of the plane. A normal is simply the vector at right angles to the plane. Optional Variables X-Axis: Both this and the y-axis are used only for mapping 2 dimentional shaders onto the surface of the plane. They should be perpendicular for a square grid, and must NOT be coplanar with the normal and eachother. Y-Axis: See above. Examples: Object Plane Position (0.0 -10.0 0.0) Normal (0.0 1.0 0.0) ; ; This defines a 'floor' ten units below the origin of the scene. Cylinders The Cylinders primitive describes a 'pipe'. Required Variables: From <vec> : A vector defining the start of the cylinder. To <vec> : A vector defining the end of the cylinder Radius <float> : The radius (!) of the cylinder Optional Variables: Capped: A keyword indicating that the ends of the cylinder should be 'filled in'. Examples: Object Cylinder From ( 10.0 0.0 0.0) To ( -10.0 0.0 0.0) Radius 1.0 Capped ; ; This describes a simple cylinder of 20 length and 1 width with capped ends. Box This primitive defines a cuboid shape with it's edges aligned along the axis. Required Variables: A (x y z) First corner of box B (x y z) Opposite corner of box Examples: Object Box a (0 0 0) b (1 1 1) ; ; This describes a simple box of with lower left corner (0 0 0) and upper right corner (1 1 1). Triangle This primitive is used to describe a triangle, which can be flat or rounded. Rounded triangles are very difficult (impossible) to hand calculate. Flat triangles can be useful to build irregular shapes. Required Variables: A (x y z) Three vectors defining the 'corners' of the triangle. B (x y z) The triangle can be viewd from both sides. C (x y z) The order of the corners is not important. Optional Variables: Normal-A (x y z) Three vectors describing the normals of the points Normal-B (x y z) at each corner of the triangle. This will provide a Normal-C (x y z) rounded triangle Examples: Object Triangle A ( 0.0 0.0 10.0) B (-5.0 0.0 0.0) C ( 5.0 0.0 0.0) ; ; This will produce a flat triangle. Raw This allows the inclusion of RAW triangle files into scene files without having to convert the raw data into triangle statements, it also allows PortRAY to compact the data by eliminating any multiple references to single points, and at the same time allows PortRAY to generate normals at each corner to smooth out the shape automatically Required Variables: FILE <filename> : This is the name of the file that contains the RAW triangle info, this MUST not have any data apart from the raw triangles. Optional Variables: WELD <float> : This defines how close two points need to be before the system welds them into one point. Default : 0.00001 SMOOTH : This tells PortRAY to generate smoothing normals once the triangle data is read in. X-ROTATION <float> : No of DEGREES to rotate the triangles about the X axis when they are read in. Y-ROTATION <float> : No of DEGREES to rotate the triangles about the Y axis when they are read in. Z-ROTATION <float> : No of DEGREES to rotate the triangles about the Z axis when they are read in. AT <vec> : The point in the model world that will be the origin for the triangles. CSG This stands for CONSTRUCTIVE SOLID GEOMETRY and is a way of defining a new shape from two others by combining them according to one of three rules (UNION, INTERSECT and SUBTRACT). because this uses two other objects as parameters, it can be NESTED to ANY level, and the material used to shade a point is the material defined by the surface that the ray actually hits, in this way you can make a die as in EXAM_006.SCE Required Variables OPERAND1 <object> : This is the first object OPERAND2 <object> : This is the second object [UNION | INTERSECT | SUBTRACT] : This defines how to combine them Operators UNION : This one just adds the two shapes together, so you could for instance add a spherical cap to the end of a cylinder. INTERSECT : This one makes the resulting shape what is inside BOTH operand1 AND operand2 SUBTRACT : This takes the second shape from the first. Example Look at EXAM_005.SCE and EXAM_006.SCE Polygon Disk Same as plane but with the inclusion of the radius <float> keyword. 8 Materials ----------- This part of a scene file allows you to define the surface characteristics of the objects that you have defined in your scene. A material definition can be created as part of the object eg: Object sphere centre (0.0 0.0 0.0) radius 1.0 ; material colour (1.0 1.0 1.0) ; ; or it can be named and used later eg: define material named flat-red colour (1.0 0.0 0.0) ; ; Object primitive sphere centre (0.0 0.0 0.0) radius 1.0 ; material called flat-red ; ; All the material options are as follows: Material called <name> named <name> colour <col> diffuse-reflection <float> diff-colour <col> specular-reflection <float> specular-power <float> spec-colour <col> reflection <float> transparency <float> tran-colour <col> refractive-index <float> <shader-name> <shader info> ; Called: references a pre-defined material (can be included from a seperate file) Named: defines a material for later use Colour : this defines the basic colour of the object, and so sets the values of all three colours (spec, diff, tran) Diff-Colour : Defines the colour used in diffuse (or Lambertian) reflection. Spec-Colour : Defines the colour used in specular reflection. Tran-Colour : Defines the colour used as the body or solid colour for transparent objects. diffuse-relection : defines the amount of reflection, a value of 1.0 gives a bright dull object, a value of 0.0 gives a dark dull object. See mats1.sce/mats1.gif specular-reflection : defines the amount of reflectivity of the material A value of 1.0 will produce a shiny surface See mats1.sce/mats1.gif specular-power : defines the 'tightness' of the specular highlights. High values will give small sharp-edged highlights while a low value will give large soft-edged highlights See mats1.sce/mats1.gif reflection : Controls the weight of the mirror reflections. transparency : Defines the transparency of the surface. A value of 1.0 will give a totally transparent surface and a value of 0.0 will give a totally opaque surface. see mats2.sce/mats2.gif refractive-index : Defines the refractive index of the material. This is an index determining the amount light gets bent as it passes from one material (air) to the other. The refractive index for glass is 1.2 <shader-name> : This section allows you to apply 'effects' to the surface. Please see the shader section for more info. 9 Shaders --------- Shaders are broken down into two major catagories 1) Those that use the 3d position of the intersection to vary the material eg, bumpy, fader, turb. 2) Those that use the 2d mapping on the intersected surface to vary the material Note if you are creating a shape out of several others either by DEFINE or CSG, and wish a single variable type shader to cover the whole object it is better to stick to the type 1 shaders above, as the 2d mappings of each seperate sub object may not mesh very well. Bricks (Type II) This simulates bricks, by accepting two other material definitions and then deciding which to use to form a brick patters, see EXAM_007.SCE note that the back wall is shaded using the brick shader. Variables : MORTAR <material> : The material that comprises the bricks BRICK <material> : The material to be used for grout SIZE <float> : This is the size of the brick texture, the greater the number, the larger the bricks Tiles (Type II) This simulates tiling, see EXAM_007.SCE, note that the floor is shaded using tiles. Variables : FACE <material> GROUT <material> TILE-WIDTH <int> GROUT-WIDTH <int> SIZE <float> Chequers (Type II) Similar to above, but simulates a chequered floor, by choosing one of two materials. Variables MATERIAL-A <material> : The materials that form the MATERIAL-B <material> : two different types of square. SIZE <float> : The size of the chequer board squares Bumpy (Type I) This simulates a bumpy surface, by "perturbing" the normal to the surface at any one point. Variables SIZE <float> : This governs the size of the bump features on all axes at once. TERMS <int> : the higher the number of turms and the rougher the bumps will get. XSIZE <float> : These three terms independantly alter the YSIZE <float> : size of the bumps in the three axes, this ZSIZE <float> : allows bark type effects to be generated MATERIAL <material> : This allows you to overlay the bumps on another material, for instance to make bumpy wood. SATURATION <float> : This is the amount of the surface that is actually bumped, 0.0 and none of the surface will be bumpy, or 3.1416 and the whole surface will be bumpy DEPTH <float> : maximum depth of perturbation, Note : surface artifacts (or acne) can be formed when the angle of intersection is close to tangential to the surface and the depth of purturbation is too high. Noise (Type I) This is similar to bozo in Pov, but can be controlled in several ways. Variables SIZE <float> : the feature size of the noise texture. MATERIAL <material> : This allows you to apply noise to another material. VARIENCE <float> : This defines the amplitude of the varience in colour that noise operates in. COLOUR <colour> : the base colour about which the varience operates. Fades (Type I) This is perhaps the MOST powerful shader available in PortRAY, and along with Turb3d (below) can be used to simulate all sorts of natural materials. (woods, cloud, granite, rusty-steel) This shader measures how far along a defined axis, a particular point is and then interpolates between colours or materials in a list, the shader accepts either a list of distances and either colours or materials. The list of entries in the material or colour list is closed by entering 0 in the float variable, for instance material fades axis (1 1 1) colours 0.1 (0 0 0) 2.0 (0 0 1) 0.0 (0 0 0) ; ; This example fades from (0 0 0) to (0 0 1) over a distance of 0.1, and then back again to (0 0 0) over a distance of 2.0. Note, never include both materials AND colours lists in a single fades command (its a BIT like crossing the beams in GhostBusters :) ) Variables AXIS <vec> MATERIALS [<float> <material>] COLOURS [<float> <colour>] Turb3d (Type I) This shader alters the 3d point that all other shaders use to base their outcome on by a 3d volume fractal based on the original position, this allows the generation of effects like wood, or cloud. Variables TERMS <int> : The roughness of the fractal or the number of iterations that the system goes through to approximate the fractal. DEPTH <float> : the maximum distance of purturbation of the 3d point. SIZE <float> : the maximum wavelength of the fractal MATERIAL <material> : the material to which the turbulence is to be applied. 10 Define --------- This is PROBABLY the MOST useful command in PortRAY. It allows you to create your own objects or named materials and from there, using them as if they where built in, also each defined object and material is only stored once, all subsiquent uses of it are stored as pointers to the original and orientation information. The syntax is as follows DEFINE [OBJECT NAME ATHING [OBJECT ... ;] ;] [MATERIAL NAMED AMATERIAL [ ANY MATERIAL SETTINGS] ;] ; Once a complex object is defined in this way, it can be used just like a builtin object, for instance :- object translate (0 0 1) ATHING ; ; object translate (1 0 0) ATHING ; ; The requirement for the ";" after ATHING in the above example is to allow a position for variables to be associated with the "ATHING". The overhead for using a complex object like this is at least 16 bytes, and at MOST about 50, so it can be very efficient to generate a heirarchy of defined objects, to create for instance a stadium full of chairs. or a large fence out of smaller simple building blocks, or indeed a wall out of larger and larger agregates of blocks. Materials can be used is a SIMILAR way, for instance :- object sphere ; material called AMATERIAL ; ; Again the material AMATERIAL is NOT copied, it is pointed to, and so takes up NO extra memory for each re-use. Appendix A. -- List and Description of EXAMPLE scene files Name Information EXAM_001 Shows difference between Diffuse and Specular REFLECTION and REFRACTION EXAM_002 Shows difference between the values of 10, 100 and 1000 as the specular-power. EXAM_003 EXAM_004 Shows the combination of specular reflection and refraction to make a glassy material. EXAM_005 Shows the three basic CSG operations EXAM_006 Shows CSG by the construction of a die EXAM_007 Shows use of TILE and Brick objects BGAMMON This and several include files generates a quite detailed view of a pine table with two tumblers and a backgammon board with brass inlays and 2 dice. Appendix B. -- ERRORLEVEL MEANINGS ErrorLevel Meaning 0 Successful Render 1 Unable to open camera file Unrecognised Keyword in camera section Unrecognised Keyword in Image section Unable to open scene file Unknown Verb in Scene file Attempt to use an object that does not support being the shape of a light. Unknown verb in Lightsource Definition Attempt to use an undefined complex object Unknown verb in Object Definition Attempt to Overlay a Material Definition with a named one Unrecognised/Undefined Material Attempt to alter characteristics of a named material Unknown verb in Material Definition Unknown verb in complex Reference Unknown verb in Definition Statement Out of memory error, Unable to allocate memort for data storage Intersection Buffer Exhausted 2 Attempt to set number of samples for a lightsource that has no defined shape. Unable to allocate extra heap space